Glaukos iStent: A Quick Review and Commentary

Jun 8, 2015

Glaukos iStent. Part 6 of 12 of “What’s New In Glaucoma Surgery” Presentation, a continuing education course for Optometrists presented by Patient-Focused Ophthalmologist, Dr. David Richardson on May 20, 2015.

Glaukos iStent: A Quick Review and Commentary

The latest buzz, the latest FDA-approved glaucoma procedure is the iStent. And a lot of people have been really excited about the iStent; and in Canada, Dr. Dr. Ike Ahmed – who is an outstanding surgeon, has been a big proponent of the iStent. And for him, I think, it works pretty well and I’ll tell you why it may work better for him in Canada than it would for us here in the US. What happens with the iStent…this is actually Ike Ahmed’s procedure. This is Gonioscopic surgery. So, that’s a Gonioprism. And this little device is the iStent. It’s a little snorkel-like device and that there is the trabecular meshwork. What we’re seeing here is Trabecular Meshwork and he’s taking the iStent and his pushing it in through the Trabecular Meshwork work and there it goes right into the canal -Schlemm’s canal. Once it’s in Schlemm’s canal, he’s going to release it and you see a little blood reflux out and that’s because…remember that the canal is connected to the collector channels which is connected into the Venus system, so when you actually open up the system you can get some reflux of blood that reflux of blood is a good thing that shows you that you’ve actually gotten into the system and the system is patent. So here’s where things differ between here and in Canada. In Canada, you can put in multiple of these little stents.

Here in the US, they only FDA-approved for one at the time cataract surgery. So Dr. Dr. Ike Ahmed has been getting great results from putting on these little stents but he’ll put in three four at a time and you can see I mean it’s really– it’s pretty neat to watch here and you can see that reflux, here. You know there’s good flow and here at the end of the case …I think he’s going to put another one. Yes, here he goes with the third one (just couldn’t do this here and I’ll tell you why). But once he puts it in he’s going to show you the actual flow through the system using some dyes. He will put some die in the eye and you’ll see the flow out through the collector channel system. That’s pretty impressive but the issue is that these stents are $1000 each they’re made out of surgical grade titanium ounce per ounce these are one of the most expensive things that you can possibly purchase I think that the only thing more expensive than these by weight is anti-matter. So, here it goes – he’s putting into this…you see the blue dye go through there? Its– he’s going to do the end, right there, you see that? That’s really – it’s neat. You see this, you think, wow! Okay, it’s a neat procedure. Its low-risk. It’s not very invasive. The thinking is, that the iStent is a good technique for somebody who’s having a cataract surgery with ocular hypertension or mild open-angle glaucoma. Can be done with cataract surgeries. So, you’re “already there”, but the problem is that it can potentially limit future surgeries. You put these tiny little iStents in. If it works really well, great! Who cares about future surgeries?

But if you’re going to need future surgeries such as Canalo-based surgeries and one of the really exciting surgeries that we either have now or will have are Canalo-based. You don’t want to close the door on something that’s going to work really well with something that “well, let’s see how well it works, shall we?” And then it’s also- like I said, it’s expensive. Like a thousand bucks a pop. Who is going to pay for that?

Does It Work?

Does it really enhance? The whole point of the iStent is to create an opening from the anterior chamber into the canal from trabecular – you know, through the trabecular meshwork. This is a really tiny little lumen. Well let’s see the results.

Cataract surgery plus the iStent? 72% Okay, Well there’s a couple ways to look at that. You can look at that say, “holy cow! Cataracts…surgery treats glaucoma in 50% of patients, right? I mean that’s what most of us saw. To me, 72% versus 50% just wasn’t that impressive. Especially for something that is expensive may not be covered by insurance, could close doors on future options…So this is one of the reasons why I’ve not started implanting these things. Now, Dr. Ike Ahmed (again) he’s learned that when you implant multiple stents, not surprisingly, you get more flow, you get the stents in near the collector channel system, you get a better result. But it’s very important with this that you place them…he’s learned you have to place them where the patent collector channels are for this to work. Okay, so, 1 year out maybe say well, “that’s good enough for me, my insurance pays for it, it’s easy, and it’s low risk. Hey 72% vs. 50%? I’ll do it!”

What about two years out? Two years out published results: Cataract surgery alone 61% of patients ended up with pressure reduction of less than 22 mmHg. The iStent, 71%. When I see, what there’s still 10 percent more…? Wait, that difference was not statistically significant, which means this doesn’t mean anything. Ten percent may not be a real difference. Could just be– you could redo the study and see those two flipped. Two years out, my reading of this is the iStent doesn’t work. Doesn’t buy you anything extra than cataract surgery alone. So, again, you got patients who have insurances that’s paying for it and they’re low risk for progressing to more advanced glaucoma it’s like an insurance policy. But if they’re paying out of pocket, I really don’t see that there’s—that they’re getting much of value.